Messages in this thread | | | Date | Mon, 16 Jan 2023 17:24:56 +0100 | Subject | Re: [PATCH v5 0/5] iommu: Retire detach_dev callback | From | Marek Szyprowski <> |
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Hi All,
On 10.01.2023 03:54, Lu Baolu wrote: > Hi folks, > > The iommu core calls the driver's detach_dev domain op callback only when > a device is finished assigning to user space and > iommu_group_release_dma_owner() is called to return the device to the > kernel, where iommu core wants to set the default domain to the device but > the driver didn't provide one. The code looks like: > > /* > * New drivers should support default domains and so the detach_dev() op > * will never be called. Otherwise the NULL domain represents some > * platform specific behavior. > */ > if (!new_domain) { > if (WARN_ON(!group->domain->ops->detach_dev)) > return -EINVAL; > __iommu_group_for_each_dev(group, group->domain, > iommu_group_do_detach_device); > group->domain = NULL; > return 0; > } > > In other words, if the iommu driver provides default domains, the > .detach_dev callback will never be called; Otherwise, the .detach_dev > callback is actually called to return control back to the platform DMA > ops, other than detaching the domain from device. > > This series cleanups this by: > > - If the IOMMU driver provides default domains, remove .detach_dev > callback. > - Adds a new set_platform_dma iommu op. Any IOMMU driver that doesn't > provide default domain should implement set_platform_dma callback > instead. > - Retire .detach_dev callback. > > This series originates from various discussion in the community. Thanks > to Jason, Robin and all others for their ideas.
I wonder how to handle the ARM 32bit case, which doesn't use the default domain solution. Today, once this patchset has been merged to linux-next, I've noticed that it broke booting of ARM 32bit Exynos based boards.
The final solution would be to switch ARM 32bit to generic DMA-IOMMU glue, but I'm not sure it this will happen soon. I will try to check if any kind of quick workaround can be applied to get it working again.
> The whole series is available on github: > https://protect2.fireeye.com/v1/url?k=ef2183b6-b0bababa-ef2008f9-000babff3563-336828b3433153d2&q=1&e=4ae5dae4-383f-4a82-9449-3f08f0422cb1&u=https%3A%2F%2Fgithub.com%2FLuBaolu%2Fintel-iommu%2Fcommits%2Fiommu-retire-detach_dev-v5 > > Change log: > v5: > - Merge some patches to make the series cute. No functionality changes. > - Check the op directly and WARN_ON the lack of any necessary > callbacks. Get rid of the ret and EINVAL. > > v4: > - https://lore.kernel.org/linux-iommu/20230104125725.271850-1-baolu.lu@linux.intel.com/ > - Drop the patch which renamed .attach_dev to .set_dev. As Robin said, > "... I also wouldn't say that "attach" loses its meaning in a context > where an equivalent "detach" operation is only ever implicit in > reattaching to something else...". If we have a better name in the > future, we can do it in other series. > - Adjust the patch of "iommu: Add set_platform_dma_ops iommu ops" > according to Jason's following suggestion " ... This is a bit ugly, > it would be better to make the previous patch call set_platform_dma > if it is set instead of detach_dev and then these patches should just > rename the driver's fsl_pamu_detach_device to > fsl_pamu_set_platform_dma ..." > - Add a new patch to remove deferred attach check from > __iommu_detach_domain() path. Make it a separate patch as the > prerequisite to remove __iommu_detach_device() helper. > - Rename set_platform_dma to set_platform_dma_ops to make it more > meaningful. > > v3: > - https://lore.kernel.org/linux-iommu/20221128064648.1934720-1-baolu.lu@linux.intel.com/ > - Setting blocking domain is not conceptually equal to detach_dev. > Dropped all blocking domain related staffs in the previous version. > > v2: > - https://lore.kernel.org/linux-iommu/20220826123014.52709-1-baolu.lu@linux.intel.com/ > - Replace .detach_dev callback with static block domain ops; > - Rename .attach_dev to .set_dev. > > v1: > - https://lore.kernel.org/linux-iommu/20220516015759.2952771-1-baolu.lu@linux.intel.com/ > > Jason Gunthorpe (1): > iommu: Remove deferred attach check from __iommu_detach_device() > > Lu Baolu (4): > iommu: Remove detach_dev callbacks > iommu: Add set_platform_dma_ops iommu ops > iommu: Add set_platform_dma_ops callbacks > iommu: Remove detach_dev callback > > include/linux/iommu.h | 8 ++- > include/trace/events/iommu.h | 7 -- > drivers/iommu/amd/iommu.c | 26 ------- > drivers/iommu/apple-dart.c | 24 ------- > drivers/iommu/arm/arm-smmu/qcom_iommu.c | 23 ------ > drivers/iommu/exynos-iommu.c | 1 - > drivers/iommu/fsl_pamu_domain.c | 6 +- > drivers/iommu/iommu-traces.c | 1 - > drivers/iommu/iommu.c | 94 ++++++++++++------------- > drivers/iommu/ipmmu-vmsa.c | 16 ----- > drivers/iommu/msm_iommu.c | 6 +- > drivers/iommu/mtk_iommu.c | 9 --- > drivers/iommu/mtk_iommu_v1.c | 4 +- > drivers/iommu/omap-iommu.c | 6 +- > drivers/iommu/rockchip-iommu.c | 1 - > drivers/iommu/s390-iommu.c | 7 +- > drivers/iommu/sprd-iommu.c | 16 ----- > drivers/iommu/sun50i-iommu.c | 1 - > drivers/iommu/tegra-gart.c | 6 +- > drivers/iommu/tegra-smmu.c | 5 +- > 20 files changed, 69 insertions(+), 198 deletions(-) > Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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